Day: June 22, 2017

An ISP dongle is a very common piece of equipment on a maker’s bench. However, its potential as a hackable device is generally overlooked. The USBASP has an ATmeg8L at its heart and [Robson] decided that this humble USB device could be used as an interface between his PC and a SNES Joypad.

A SNES controller required three pins to communicate with a host: clock, data and latch. In his hack, [Robson] connects the controller to the ISP interface using a small DIY adaptor and programs the AVR using the V-USB library. V-USB is a software USB library for small microcontrollers and comes in pretty handy in this instance.

[Robson] does a pretty good job of documenting the entire process of creating the interface which includes the USB HID code as well as the SNES joypad serial protocol. His hack works on both Windows and Linux alike and the code is available on GitHub for download.

Simple implementation like this project are a great starting point for anyone looking to dip their toes in the DIY USB device pool. Veterans may find a complete DIY joystick more up their alley and will be inspired by some plastic techniques as well.

For those who have never experienced kickback on a table saw, we can assure you that at a minimum it will set your heart pounding. At the worst, it will suck your hand into the spinning blade and send your fingers flying, or perhaps embed a piece of wood in your chest or forehead. Riving knives mitigate such catastrophes by preventing the stock from touching the blade as it rotates up out of the table. Contractor table saws like [Craft Andu]’s little Makita are often stripped of such niceties, so he set about adding one. The essential features of a proper riving knife are being the same width as the blade, wrapping closely around it, raising and lowering with the blade, and not extending past the top of the blade. [Craft Andu] hit all those points with his DIY knife, and the result is extra safety with no inconvenience.

It only takes a few milliseconds to suffer a life-altering injury, so be safe out there. Even if you’re building your own table saw, you owe it to yourself.

[James West] has a young Doctor Who fan in the house and wanted to build something that could be played with without worrying about it being bumped and scratched. So, instead of creating a replica, [James] built a simple remote controlled K9 toy for his young fan.

K9 was a companion of the fourth Doctor (played by Tom Baker) in the classic Doctor Who series. He also appeared in several spin-offs. A robotic dog with the infinite knowledge of the TARDIS at hand, as well as a laser, K9 became a favorite among Who fans, especially younger children. [James] wanted his version of K9 to be able to be controlled by a remote control and be able to play sounds from the TV show.

Using some hand-cut acrylic, [James] built K9’s body, then started on plans for the motion control and brains. [James] selected the Raspberry Pi Zero for the controller board, a Speaker pHat for the audio, a couple of motors to move K9 around, and a motor controller. K9 is controlled by a WiiMote and has a button on his back to start pairing with the WiiMote (K9 answers with “Affirmative” when the pairing is successful.) When it came to the head, [James] was a little overwhelmed by trying to make the head in acrylic, so he got some foam board and used that instead. A red LED in the head lights up through translucent red acrylic.

It’s a great little project and [James] has put the Python code up on Github for anyone interested. We’ve had a couple of robot dog projects on the site over the years, like this one and this one.

Potatoes deserve to roam the earth, so [Marek Baczynski] created the first self-driving potato, ushering in a new era of potato rights. Potato batteries have been around forever. Anyone who’s played Portal 2 knows that with a copper and zinc electrode, you can get a bit of current out of a potato. Tubers have been powering clocks for decades in science classrooms around the world. It’s time for something — revolutionary.

[Marek] knew that powering a timepiece wasn’t enough for his potato, so he picked up a Texas Instruments BQ25504 boost converter energy harvesting chip. A potato can output around 0.4 V at 0.6 mA. The 25504 uses this power to slowly charge a capacitor. Every fifteen minutes or so, enough energy is stored to power a motor for a short time. [Marek] built a car for his potato — or more fittingly, he built his potato into a car.

The starch-powered capacitor moves the potato car about 8 cm per cycle. Over the course of a day, the potato can travel around 7.5 meters. Not very far, but hey, that’s further than the average potato travels on its own power. Of course, any traveling potato needs a name, so [Marek] dubbed his new pet “Pontus”. Check out the video after the break to see the ultimate fate of poor Pontus.

[Neil K. Sheridan]’s Automated Elephant Detection System was a semi-finalist in last year’s Hackaday Prize. Encouraged by his close finish, [Neil] is back at it with a refreshed and updated Elephant AI project.

The purpose of Elephant AI is to help humans and elephants coexist by eliminating contact between the two species. What this amounts to is an AI that can herd elephants. For this year’s project, [Neil] did away with the RF communications and village base stations in favor of 4G/3G-equipped, autonomous sentries equipped with Raspberry Pi computers with Go Pro cameras.

The main initiative of the project involves developing a system able to classify wild elephants visually, by automatically capturing images and then attempting to determine the elephant’s gender and age. Of particular importance is the challenge of detecting and controlling bull elephants during musth, a state of heightened aggressiveness that causes bulls to charge anyone who comes near. Musth can be detected visually, thanks to secretions called temporin that appear on the sides of the head. If cameras could identify bull elephants in musth and somehow guide them away from humans, everyone benefits.

This brings up another challenge: [Neil] is researching ways to actually get elephants to move away if they’re approaching humans. He’s looking into nonlethal techniques like audio files of bees or lions, as well as ping-pong balls containing chili pepper.

Have you, dear reader, ever needed to plot the position of a swimming pool noodle in 3D and in real time? Of course you have, and today, you’re in luck! I’ve compiled together a solution that’s sure to give you the jumpstart on solving this “problem-you-never-knew-you-had.”

Ok, there’s a bit of a story behind this one. Back in my good-ol’ undergrad days, I got the chance to play with tethered underwater robots. I remember fumbling about thinking: “Hmm, with this robot tether, wouldn’t it be sweet to string up a set of IMUs down the length of the tether to estimate the robot’s location in 3-space?” A few years later, I cooked together this IMU Noodle project to play with some real hardware in the spirit of solving that problem. With a little quaternion math, a nifty IMU, and some custom PCBAs, this idea has gone from some idle brain-ramble into a real device. It’s an incredibly interesting example of using available hardware and a little ingenuity to build a system that is unique and dependable.

As for why? I first saw an IMU noodle pop up on these pages back in 2012 and I was baffled. I just had to build one! Now complete, I figured that there’s enough math and fun-loving electronics nuggets to merit a full article for this month’s after-hour adventures. Dear reader, let me tell you a wonderful story where math meets electronics and works up the courage to ask it out for brunch.

The Internet has brought a lot of advantage to life, not the least of which is access to really cheap electronic parts. [KarelK166] was buying cheap geared motors for projects, but they didn’t easily work with Lego blocks. He found an easy way to adapt them and–lucky for us–decided to share.

The process is pretty simple. The gearbox has two screws and an elastic band holding it together. Once the gears are exposed, you can drill a hole in two of them with a 4.8mm drill bit. This might take a little practice since the gear needs to hold still, but you also don’t want to crush the plastic teeth. You also need to enlarge a hole in the casing, but that’s easier to clamp down in a vise.